Thistle

Cirsium ×iowense

Native to:
United States

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Taxonomy

Division:
Magnoliophyta | - Flowering plants
Family:
Asteraceae
Genus:
Cirsium
Species:
Cirsium ×iowense
USDA Symbol:
CIIO2

Growth Characteristics

Life Cycle:
Perennial
Growth Habit:
Forb/herb
Height:
150 cm
Light Requirements:
Full Sun
Drought Tolerance:
Medium
Bloom Months:
jun,jul,aug,sep
Bloom Colors:
pink, purple

Wildlife Benefits

Bees:
★☆☆☆☆ Documented bee visitation (GBIF)
Butterflies & Moths:
★☆☆☆☆ Documented Lepidoptera association (GBIF)

Keystone Species Ranking

Pollen Specialist Bee Keystone:
★★☆☆☆ Native pollen specialist bee species supported by this genus (NWF)

Garden & Ecology Notes

Wildlife Value:
bees, butterflies, birds
Deer Resistant:
Yes
Fire Ecology:
Fire adapted — tolerates or benefits from fire
Fire Notes:
Resprouts from root crown following fire; typical of prairie thistles adapted to periodic burning.

Soil Requirements

Soil Type:
rich, well-drained loamy soil
pH:
5.5 - 7.0 (slightly acidic to neutral)
Drainage:
excellent drainage required
Moisture:
consistently moist
Notes:
Prefers open, sunny habitats with good air circulation

Propagation & Germination

Stratification:
Cold/moist stratification required — 30–60 days
Germination Time:
14–30 days
Notes:
Cold stratification improves germination rates. Seeds require light for optimal germination.

The above propagation data sourced from Claude AI

Pre-treatment: Cold-moist stratification for 30 days at 1–5°C (34–41°F).

Source: Claude AI